Imported existing code

libraries/include/boost/wave/util/transform_iterator.hpp

@@ -0,0 +1,169 @@
+/*=============================================================================
+    Boost.Wave: A Standard compliant C++ preprocessor library
+
+    http://www.boost.org/
+
+    Copyright (c) 2001-2009 Hartmut Kaiser. Distributed under the Boost
+    Software License, Version 1.0. (See accompanying file
+    LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+=============================================================================*/
+
+#if !defined(TRANSFORM_ITERATOR_HPP_D492C659_88C7_4258_8C42_192F9AE80EC0_INCLUDED)
+#define TRANSFORM_ITERATOR_HPP_D492C659_88C7_4258_8C42_192F9AE80EC0_INCLUDED
+
+#include <boost/config.hpp>
+#include <boost/iterator_adaptors.hpp>
+#if BOOST_ITERATOR_ADAPTORS_VERSION >= 0x0200
+#include <boost/iterator/transform_iterator.hpp>
+#endif // BOOST_ITERATOR_ADAPTORS_VERSION >= 0x0200
+
+#include <boost/assert.hpp>
+
+// this must occur after all of the includes and before any code appears
+#ifdef BOOST_HAS_ABI_HEADERS
+#include BOOST_ABI_PREFIX
+#endif
+
+///////////////////////////////////////////////////////////////////////////////
+namespace boost {
+namespace wave { 
+namespace impl {
+
+#if BOOST_ITERATOR_ADAPTORS_VERSION < 0x0200
+
+///////////////////////////////////////////////////////////////////////////////
+// 
+//  Transform Iterator Adaptor
+//
+//  Upon deference, apply some unary function object and return the
+//  result by reference.
+//
+//  This class is adapted from the Boost.Iterator library, where a similar 
+//  class exists, which returns the next item by value
+//
+///////////////////////////////////////////////////////////////////////////////
+    template <class AdaptableUnaryFunctionT>
+    struct ref_transform_iterator_policies 
+    :   public boost::default_iterator_policies
+    {
+        ref_transform_iterator_policies() 
+        {}
+        ref_transform_iterator_policies(const AdaptableUnaryFunctionT &f) 
+        : m_f(f) {}
+
+        template <class IteratorAdaptorT>
+        typename IteratorAdaptorT::reference
+        dereference(const IteratorAdaptorT &iter) const
+        { return m_f(*iter.base()); }
+
+        AdaptableUnaryFunctionT m_f;
+    };
+
+    template <class AdaptableUnaryFunctionT, class IteratorT>
+    class ref_transform_iterator_generator
+    {
+        typedef typename AdaptableUnaryFunctionT::result_type value_type;
+        
+    public:
+        typedef boost::iterator_adaptor<
+                IteratorT,
+                ref_transform_iterator_policies<AdaptableUnaryFunctionT>,
+                value_type, value_type const &, value_type const *, 
+                std::input_iterator_tag>
+            type;
+    };
+
+    template <class AdaptableUnaryFunctionT, class IteratorT>
+    inline 
+    typename ref_transform_iterator_generator<
+        AdaptableUnaryFunctionT, IteratorT>::type
+    make_ref_transform_iterator(
+        IteratorT base,
+        const AdaptableUnaryFunctionT &f = AdaptableUnaryFunctionT())
+    {
+        typedef typename ref_transform_iterator_generator<
+                    AdaptableUnaryFunctionT, IteratorT>::type 
+            result_t;
+        return result_t(base, f);
+    }
+
+    //  Retrieve the token value given a parse node
+    //  This is used in conjunction with the ref_transform_iterator above, to
+    //  get the token values while iterating directly over the parse tree.
+    template <typename TokenT, typename ParseTreeNodeT>
+    struct get_token_value {
+
+        typedef TokenT result_type;
+        
+        TokenT const &operator()(ParseTreeNodeT const &node) const
+        {
+            BOOST_ASSERT(1 == std::distance(node.value.begin(), 
+                node.value.end()));
+            return *node.value.begin();
+        }
+    };
+
+#else // BOOST_ITERATOR_ADAPTORS_VERSION < 0x0200
+
+///////////////////////////////////////////////////////////////////////////////
+//
+//  The new Boost.Iterator library already conatins a transform_iterator usable 
+//  for our needs. The code below wraps this up.
+//
+///////////////////////////////////////////////////////////////////////////////
+    template <class AdaptableUnaryFunctionT, class IteratorT>
+    class ref_transform_iterator_generator
+    {
+        typedef typename AdaptableUnaryFunctionT::result_type   return_type;
+        typedef typename AdaptableUnaryFunctionT::argument_type argument_type;
+        
+    public:
+        typedef boost::transform_iterator<
+                return_type (*)(argument_type), IteratorT, return_type>
+            type;
+    };
+
+    template <class AdaptableUnaryFunctionT, class IteratorT>
+    inline 
+    typename ref_transform_iterator_generator<
+        AdaptableUnaryFunctionT, IteratorT>::type
+    make_ref_transform_iterator(
+        IteratorT base, AdaptableUnaryFunctionT const &f)
+    {
+        typedef typename ref_transform_iterator_generator<
+                AdaptableUnaryFunctionT, IteratorT>::type
+            iterator_type;
+        return iterator_type(base, f.transform);
+    }
+
+    //  Retrieve the token value given a parse node
+    //  This is used in conjunction with the ref_transform_iterator above, to
+    //  get the token values while iterating directly over the parse tree.
+    template <typename TokenT, typename ParseTreeNodeT>
+    struct get_token_value {
+
+        typedef TokenT const &result_type;
+        typedef ParseTreeNodeT const &argument_type;
+        
+        static result_type
+        transform (argument_type node) 
+        {
+            BOOST_ASSERT(1 == std::distance(node.value.begin(), 
+                node.value.end()));
+            return *node.value.begin();
+        }
+    };
+
+#endif // BOOST_ITERATOR_ADAPTORS_VERSION < 0x0200
+    
+///////////////////////////////////////////////////////////////////////////////
+}   // namespace impl
+}   // namespace wave
+}   // namespace boost
+
+// the suffix header occurs after all of the code
+#ifdef BOOST_HAS_ABI_HEADERS
+#include BOOST_ABI_SUFFIX
+#endif
+
+#endif // !defined(TRANSFORM_ITERATOR_HPP_D492C659_88C7_4258_8C42_192F9AE80EC0_INCLUDED)